conflict error?

SloPo

Greetings,
I am working with a Basic Stamp 2 Module and its related Carrier Board. I have hooked up to the board a GPS Sensor and Ultrasonic Range Finder (PING). Individually, each component works extremely well with the module and I am able to program it to do whatever I need. However, when both components are hooked up at the same time (sharing the VDD pin) I am consistantly getting errors when trying to execute the program. Also, the GPS Reciever can not recieve a satellite signal. (however when the PING sensor is disconnected, it aquires a signal well). Enclosed is a picture of the appartus that we're using. (Its for a senior project, dont mind the truck its sorta mounted to. The error we're receieving is "Hardware Communication Failure: Check Connection and Power Supply."
Can anyone help with this?
I have the program available if it may be that. It basically is the GPS demo and PING demo with unncessary values stripped out. We only want speed (from GPS) and distance (PING).
~Jon

stamptrol

If you're "sharing" Vdd, you're trying to power the external equipment with the Stamp's voltage regulator. It is not designed to supply very much external current.

What's happening is the external equipment is drawing too much current, over-heating the regulator and it is shutting down to protect itself.

Power the external stuff with a second voltage reg fed from Vin. Make sure Ground (Vss) is common to both the Stamp and the external equipment.

Cheers,

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Tom Sisk

http://www.siskconsult.com
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JD

Jon,
·
Can you post the combined code so we can review it ( you can use the attachment manager )? Also what is the power supply being used?·It would need to provide enough to run both modules at the same time for everything to run properly.

I do not think the picture came through; as it is not attached to the post. There is a maximum of 2048KB for picture size, perhaps the picture was exceeding the size.

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Respectfully,


Joshua Donelson
www.parallax.com

SloPo

thanks for the quick reply. joshua,·here's the code if it helps you.

Jon

JD

Jon,

There are a few suggestions I would make in regards to the program. It seems that if you acquire the satellite signal prior to getting the PING))) information it seems to work·better. However, I used a BOE w/ 7.5 V 1A wall adapter to supply enough current for all the modules.

There is still some debugging placement that needs to be refined, but if you place the GOSUB Get_Sonar and subsaquent routines after the GPS has lock, you should be able to get both signals consistently; then you can work out the debug refining from there.

Try something like this:

Main:
·DO
· GOSUB Get_Valid
· GOSUB Get_Sats
· GOSUB Get_Speed
· GOSUB Get_Sonar
· *subsaquent PING))) routines*
LOOP

In your DO…LOOP, you will not need the END command; as it will never get to that point.

I hope this helps

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Respectfully,


Joshua Donelson
www.parallax.com

huynh

Hi John,

I do not know that whether you have solve your problem or not. I had experience with the problem that you mention. my solution is: try to power the sensor with external power source. I think the internal regulator of BStamp can not supply enough current for the sensors.

Pthien,

JD

Jon,

That is a good point to bring up Pthien; I was using the BOE on-board 5 volt regulator to power the modules, not the BS2's regulator. Thank you for the addition.

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Respectfully,


Joshua Donelson
www.parallax.com

SloPo

Joshua,

thanks for the advice for the power source, it fix the problem i had. the program runs smoothly now. i forgot to mention that the power source we were using before you gave me the power source advice, i was using a 9 volt battery. is that too much? since you stated that you used a BOE 7.5v. another thing, i was reading and i saw that you were using a BOE, what is that? and where can i get this BOE on-board 5 volt regulator? is that something i need to buy how does it attach to the stamp, does it need to be connected to an outlet? thanks for the help.

jon

SloPo

Here's a half-a$$ed image of what the "prototype" looks like. (keep the comments to a minimum, this is an extreme prototype design lol)

JD

Jon,

You can get a Board of Education (BOE) from the Parallax web site; however since you already have a development board you could just implement a 5 volt regulator on your board and use it to power the components and take the load off the BS2.

All you would need to do it connect the 9 volt supply (or a jumper from the Vin pin) to the input pin of the regulator, connect the ground of the regulator (to give a common ground) to Vss, and use the output to make a new regulated supply. This will allow you to output much more than the BASIC Stamp is set up for. You would also want to put a cap to stabilize the power; for example a 1000µF cap across Vss and Vin (make note on the connections of the cap; if backwards it can, and most likely will explode, stink something terrible too).

Here is a link to the 5 V regulator that I was using; you can pick up a 1000µF electrolytic cap from various hobby stores, Radio Shack, or any electronics store for dirt cheap.

5 volt LDO Regulator [noparse][[/noparse] there is a datasheet to help with connections, or you can review a schemcatic of·a BOE·below ]:
http://www.parallax.com/Store/Components/IntegratedCircuits/VoltageRegulator/tabid/615/CategoryID/80/List/0/SortField/0/Level/a/ProductID/242/Default.aspx

BOE [noparse][[/noparse] schematic ]:
http://www.parallax.com/Portals/0/Downloads/docs/prod/boards/BOERevC.pdf

Good job; the truck looks a lot more fun.


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Respectfully,


Joshua Donelson
www.parallax.com